Echeneibothrium, van Beneden, 1850

Franzese, Sebastián, Mutti, Leonardo D., Tropea, Carolina & Ivanov, Verónica A., 2022, Morphological study of members of the genus Echeneibothrium (Cestoda: Rhinebothriidea: Echeneibothriidae) from rajiform skates of the Argentine Sea and analysis of the phylogenetic relationships within the family Echeneibothriidae, Zoologischer Anzeiger 299, pp. 1-20 : 15-17

4.1. The genus Echeneibothrium and its hosts in the Argentine sea

In the present study we describe a new species of Echeneibothrium from the Magellanic Province in southern Argentine Sea. Unlike most congeners that parasitize Rajidae skates ( Ruhnke et al. 2017; Benmeslem et al. 2018), Echeneibothrium cristinae sp. nov. was found in a Arhynchobatidae batoid (i.e., B. cousseauae ). It is, therefore, the second species of Echeneibothrium reported in batoids of that family, along with E. pollonae , which parasitizes B. richardsoni from northwestern Atlantic Ocean ( Campbell 1977). Echeneibothrium cristinae sp. nov. could be the same species recorded by Beer et al. (2019) in B. cousseauae at the Malvinas Islands in the Argentine Sea, which was analyzed at a molecular rather than morphological level. These authors also reported specimens of Echeneibothrium parasitizing six species of the genus Bathyraja (i.e., Bathyraja albomaculata ( Norman, 1937) , Bathyraja brachyurops ( Fowler, 1910) , Bathyraja griseocauda ( Norman, 1937) , Bathyraja macloviana ( Norman, 1937) , Bathyraja multispinus ( Norman, 1937) , Bathyraja scaphiops ( Norman, 1937)) from the same region. Considering that none of them have so far been recorded as hosts for Echeneibothrium and that most marine rhinebothriideans show a high degree of specificity for their definitive hosts, it is highly probable that several of the Echeneibothrium species reported by Beer et al. (2019) are as of yet undescribed species. Further morphological studies are necessary to identify them at a specific level.

On the other hand, we made some emendations to the descriptions and redescriptions of E. multiloculatum and E. williamsi by Carvajal & Dailey (1975) and Bueno & Caira (2017), who recorded the species in D. chilensis from the Chilean Sea. Both a new host (i.e., D. brevicaudatus ) and additional localities along the Argentine Sea are reported in the present study.